Research Fellow University of Pennsylvania Kennett Square, Pennsylvania
Characterization and Immunomodulatory Properties of Extracellular Vesicles Isolated from Bone Marrow-Derived Mesenchymal Stem Cells. Gaesser AM1, Even KM1, Linardi R1, DeRita R2, Anis EA3, Stefanovski D1, Ortved K1. 1University of Pennsylvania, School of Veterinary Medicine, New Bolton Center, Kennett Square, PA; 2University of Pennsylvania, School of Veterinary Medicine, Extracellular Vesicle Core, Philadelphia, PA; 3University of Pennsylvania, School of Veterinary Medicine, Department of Pathobiology, Kennett Square, PA.
The bioactive properties of mesenchymal stem cells (MSCs) may be in part due to production of extracellular vesicles (EVs). EVs released from MSCs decrease inflammation within the joint, making them an excellent candidate for treatment of osteoarthritis (OA). Our objective was to characterize EVs isolated from equine bone marrow-derived MSCs (BM-MSCs) and investigate their immunomodulatory properties. We hypothesized that EVs isolated from equine BM-MSCs conditioned with interferon gamma (IFN-γ) would have superior immunomodulatory properties. BM-MSCs were cultured and stimulated with IFN-γ. Unstimulated cells served as the control. Cell culture supernatant was collected for isolation of EVs using ultracentrifugation. Nanoparticle tracking analysis and transmission electron microscopy characterized the size, concentration, and shape of EVs. Western blot analysis determined if EV markers were present. T cell proliferation and regulatory T cell assays and microRNA sequencing are being performed. EVs were successfully isolated and exhibited expected EV characteristics. There was no difference in the concentration of EVs between the stimulated and unstimulated groups, and preliminary data showed both MSCs and EVs derived from stimulated MSCs suppressed T cell proliferation. The remainder of the results are pending. Isolation of EVs via ultracentrifugation was simple and practical, however other methods of EV isolation may result in a higher yield. Limitations include the in vitro nature of the study. Future results will help determine if the immunomodulatory properties of EVs would make them beneficial for the treatment of OA. EVs could serve as a standardized off-the-shelf biotherapeutic, with potential for decreased immunogenicity compared to MSCs.